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A carbohydrate component of plant cell walls; associated with sieve plates where calluses are formed.
Having hardened protuberances, as on the skin or on leaves and stems.



a polysaccharide, insoluble in water, contained in plants and consisting of glucose-molecule residues joined in a spiral chain (as opposed to cellulose, in which the glucose molecules are joined in a straight chain).

Callose lines the tubules of the sievelike layers of phloem; asthese tubules age, the amount of callose increases and the tubulesbecome plugged and cease functioning. When a plant is injured, callose is deposited on the cell walls of the parenchyma, forminga callus. Callose is also found in the cell walls of some algae andfungi.

References in periodicals archive ?
Abnormal callose response phenotype and hyper-susceptibility to Peronospora parasitica in defense-compromised Arabidopsis nim 1-1 and salicylate hydroxylase-expressing plants.
Aluminum tolerance of maize cultivars as assessed by callose production and root elongation.
Callose content was determined by using a JASCO Spectrofluorometer FP-777 (Japan Spectroscopic Co, Ltd, Tokyo) with excitation at 350 nm and emission at 500 nm.
Callose staining indicates numerous cytoplasmic connections between bundle sheath cell prolongations and neighboring non-vascular cells.
Using immunofluorescence and immunogold electron microscopy techniques, we characterized the distribution of various cell wall polysaccharides namely, callose, cellulose, and pectins.
By October, Cummings Carson said, callose tissue should have formed around some canker margins if the introduced hypovirulent strain is reproducing.
After the dissolution of the callose wall, the sporopollenin wall begins to form.
The sporocyte wall, usually consisting of callose or mucopolysaccharides, isolates cells programmed to enter the meiotic pathway from the influence of surrounding vegetative cells.
Sucrose utilization via invertase and sucrose synthase with respect to accumulation of cellulose and callose in wheat roots under oxygen deficiency.
Genotypic and Developmental Evidence for the Role of Plasmodesmatal Regulation in Cotton Fiber Elongation Mediated by Callose Turnover.